Extending or Renovating in 2022? 6 Ways to Avoid the Mistakes Most People Make

Having building work done will be one of the most expensive things you ever do. In our experience, home extension/renovation projects typically cost £150,000-£500,000. A lot of money.


How do you make sure you get the most for your hard-saved funds?


How do you avoid becoming those people on Grand Designs: frustrated, over budget, and constantly compromising? These are the 6 things we think homeowners should remember:


1. Make the most of the space you already have first

Have you examined your options before thinking about extending: digging and pouring new foundations (and getting rid of the soil and rubble from excavation) is carbon intensive and expensive, and is more expensive if you live in a city with more limits on using diggers or locating a skip.


Does your house seem to have lots of corridors, redundant chimneys, nooks and crannies that seem like a waste of space? Can your budget be better spent on rearranging your current layout to get the most out of it, with money saved on external works instead used for nicer fixtures, to insulate, reduce energy bills, and improve comfort?


2. Don’t use a cheap builder!

You get what you pay for! When building work goes wrong, it tends to do so with extreme consequences. Unlike with architects, building contractors are not regulated, so the barriers to entering the profession are low. Unfortunately this means you have to be vigilant. Check your builder’s references. Check they aren’t on the Register of Disqualified Directors.


Is there a convincing reason why their price is much less than other builders’ prices for the same work? Are you being pressured to make a decision unreasonably quickly? Have you been told you don’t need a full contract, or that an architect inspecting their work will mean they’ll have to charge extra or they won’t do the project?


And do those things sound reasonable to you?


3. Know the consultancy costs

As a rough rule of thumb, set aside an additional 15% of your build budget to cover the cost of: architect, structural engineer, planning application fees, Approved Inspector (for a completion certificate), party wall surveyor, water authority fees if building near a sewer. The list can be longer depending on your project.


4. Unexpected things happen: have a budget cushion, and protect it like a child!

When agreeing a price with a builder, keep 10% extra aside. When dealing with existing buildings, unexpected things crop up, sewer pipes are discovered or need repairing, material prices fluctuate.


5. Beware scope creep. ‘We have the builders in, we might as well do this too.'

Scope creep means budget creep.


You’re in control of budget. Know the limits of what you want to do, and stick to them to preserve your budget.


Remember the powerful and disruptive concept of buyer’s remorse. The day after you’ve agreed and signed off the design of your lovely new kitchen and it’s off to be manufactured, you see something equally nice but completely different on Pinterest, and initiate an about turn, leading to more design fees and delays. Make a decision, know why you’re making it, and stick to it.


Later changes are seriously costly! On site you decide you want a wall moved by half a metre - what does that mean for the structural design (and engineers' fees?), will what you're building still comply with Building Regulations / planning permission?


6. If it hasn’t been drawn or specified, you risk disappointment when it’s built

The job of an architect, after getting you planning permission, is to document what you need in the detail a builder needs. These documents include drawings (where the lightswitches, lights, and sockets go, which way the kitchen cupboards open, how much insulation goes in the floor, walls, etc.) - the list goes on.


Most projects we do need about 15 sheets of drawings, and 15 pages of written specification. Drawings and specifications are part of the contract with your builder.


With detailed documents the project can be priced accurately, unsightly fudges on site can be avoided, and you know what you are getting. You can ask the builder to put things right if they haven’t done what’s on the drawings/specification.